Sewing rib

ABSTRACT

A sewing rib for use upon insoles in the processing of welt shoes is provided with a heat-retaining two-layer coating of adhesive material and utilized in the process of securing the sewing rib to the surface of an insole. The base adhesive layer adhered to the rib contains a dark filler and the second layer adhered to the base layer is heat-softenable and transmits infrared radiation. In use, the rib is subjected to a source of heat and immediately thereafter the coated rib surface is pressed upon the surface of an insole, whereby the adhesive is softened and rendered tacky by the heat and the darkened adhesive coating retains the heat until after the rib has been pressed upon the insole.

United States Patent [1 1 Perry et al. 5

[111 3,846,920 [451. Nov. 12, 1974 SEWING RIB [75] Inventors: Reginald P. Perry, Wellesley; Nils W. Sjoberg, Lynn, both of Mass.

[73] Assignee: Prime Manufacturing Company,

Lynn, Mass.

[22] Filed: Oct. 30, 1973 [21] Appl. No.: 411,294

[52] US. Cl. 36/22 A, 161/119 [51] Int. Cl A43b 13/00 [58] Field of Search 36/22 R, 22 A, 57; 161/102, 119

[56] References Cited UNITED STATES PATENTS 2,458,500 1/1949 Bertrand et al. 36/22 R 2,985,555 5/1961 Sherbrook v 36/22A 12/1962 Strickland 36/22 A 3,232,820 2/1966 Churchill l6l/l02 Primary ExaminerPatrick DfLawson Attorney, Agent, or Firm-Kenway & Jenney 5 7 ABSTRACT A sewing rib for use upon insoles in the processing of welt shoes is provided with a heat-retaining two-layer coating of adhesive material and utilized in the process of securing the sewing rib to the surface of an insole. The base adhesive layer adhered to the rib contains a dark filler and the second layer adhered to the base layer is heat-softenable and transmits infrared radiation. In use, the rib is subjected to a source of heat and immediately thereafter the coated rib surface is pressed upon the surface of an insole, whereby the adhesive is softened and rendered tacky by the heat and the darkened adhesive coating retains the heat until after the rib has been pressed upon the insole.

3 Claims, 6 Drawing Figures /F'IBRE BOARD CORE, 66

PATENTEUNUY 12 m4 3' sum 1 or 2 RIB -v SUPPLY SUPPORT 5 D 4 E m mw S ME YE w rlyLHAH R E ME i Bs P R I AFOF FBOTOF 6 7 x B 4: I i 4 2 6 m \a 8 F m. H kn Q 8 2 FIG. 2

PATENTEUNUV 12 1914 3.846.920

SHEH- a or 2 FIG 4 1 Y SEWING RIB BACKGROUND or THE INVENTION In conventional welt shoemaking it has been customary to provide a sewing rib comprising a fabric tape enfolded about a core strip of fiberboard and to cement the sewing rib upon the lower surface of an insole in order to provide an anchorage to which the overlasted margin of an upper may be sewn in the conventional inseaming operation. Such arrangements are clearly disclosed in US. Pat. No. 3,414,922 issued to C. G. Melanson Dec. '10, 1968 and in U.S. Pat. No. 2,654,405 issued to A. R. Ridderstrom Jan. 15, I952, n.b. FIG. 2 of the latter patent which are incorporated herein by reference.

Prior to our invention it has been deemed necessary to apply a coating of cement to the sewing rib and also to the surface of the insole. Sometimes a peripheral band of cement is deposited upon the surface of the insole; sometimes the fiberboard sheet, from which insoles are blanked out, is provided with a continuous layer of cement. In either case the coatings must be activated, usually by solvent, before the rib can be applied to the insole. The solvent fumes which result present the hazard of fire, and in any event coating equipment must be provided. Difficulties have been encountered in the use of insoles cut from coated fiberboard because of aging and non-uniform coatings. Moreover, drying racks are essential inasmuch as the activated cement requires some hours to dry.

SUMMARY OF THE INVENTION The prior difficulties and disadvantages associated with the use of sewing ribs cemented upon insoles are obviated by the system of our invention. Uponthe surface of a conventional sewing rib we apply one or more base layers of an adhesive darkened by the addition of carbon black or the like and adapted to bond well with the fabric of the rib. Over the base layer, we apply one or more top layers of atransparent adhesive adapted to makea good bond to the fiberboard insole and to the base layer. The sewing rib is fed from a reel through an enclosure provided with a heat source which causes the adhesives to soften and become tacky; the rib then is immediately applied to an uncoated insole blank. The darkened adhesive layer retains the heat during the ribapplying operation and subsequently both layers cure or crystallize into a permanent bond uniting the rib and insole. No solvents are required, no coating equipment is needed in the shoe factory, and drying racks are elim inated.

DESCRIPTION OF SPECIFIC EMBODIMENTS As used herein, the terms base layer or first layer define the adhesive layer or layers containing the dark filler which is adhered directly to the rib. The terms top layer or second layer define the adhesive layer or layers adhered to the base layer which transmit infrared radiation to permit radiation absorption by the-dark filler.

The several objects and features of the invention will be more readily understood and appreciated from the following detailed description of the preferred embodi- FIG. 1 is A view in sideelevation of a rib-applying machine as modifiedto carry out the process of the invention,

FIG. 2 is a view in cross-section taken along the lines 22 of FIG. 1,

FIG. 3 is a fragmentary view in front elevation of the heated rib receiving and guiding member.

FIG. 4 is a view in perspective of the heated rib receiving and guiding member,

FIG. 5 is a circuit diagram illustrating the electrical control system for the rib-applying machine, and

FIG. 6 is a greatly enlarged cross-section of the sewing rib.

The general organization of the rib-applying machine is well illustrated in US. Pat. No. 3,414,922 issued Dec. 10, 1968 to C. G. Melanson and in such other prior patents as US. Pat. NO. 1,794,204 issued Feb. 24, 1931 to A. R. Ridderstrom and US. Pat. No. 2,903,723 issued Sept. 15, 1959 to E. H. Hanson et al. which are incorporated herein by reference. Those skilled in the art will readily understand the structure and operation of such machines, and we shall here describe only the modification thereof required for the practice of our invention.

The rib-applying machine is organized about a main frame 10 upon which is pivotally mounted an arm 12 fitted with a handle 14 and carrying an idler roll 16 mounted on a stub shaft 18. Poised above the roll 16 is a pair of feed fingers 20 operating as disclosed in the above-identified Ridderstrom patent to cooperate with the idler roll 16 in feeding an insole blank 22 inwardly of the machine and simultaneously to press the base flanges of a sewing rib 24 upon the upper surface of the insole blank. The machine operates to begin applying the rib to the insole at one side of the heel breast line, then forwardly, then around the toe and back to the heel breast line on the opposite side of the blank. The rib is then usually cut, although, as illustrated in the above identified Melanson patent, the rib may be carried around the heel and back to the starting point.

In the practiceof our invention the applying machine has been modified in certain respects. Attached to the upper part of the machine is an elongated metal housing 26 of rectangular cross-section within which is secured a reflector 28 preferably parabolic in section, and associated with an infrared heat lamp 30 mounted in suitable brackets 32 and controlled by a toggle switch 34 secured to the outer surface of the housing 26. We have found that a sixteen inch lamp-operating at 220 volts A.C. will generate about 180 F in the repose.

which: I

The reflector housing 26 is provided internally with a series of guide pins 36 and an idler pulley 38 at each end. The sewing rib 24 feeds from a coil (not shown) over the first pulley 38, through the housing 26, over the exit pulley 38 and then over an idler pulley 40 mounted in a bracket 42 secured to the lower end of the housing 26.

As best shown in FIGS. 3 and 4 an L-shaped bracket 50 is provided in its lower leg with a hollow passage 52 connected through a side wall 54 to an inlet pipe 56. The passage 52 has an exit opening 58. Bolted to the upright leg of the bracket 50 is a block having a curving bottom 62 adjacent a slot 64. The sewing rib 24, which comprises a fabric strip 64 enfolding a fiberboard core strip 66, is supplied in flat folded condition as shown in FIG. 2. As it is pulled across the bottom 62 of the block 60, the rib is unfolded, the inner base flange being opened outwardly, while the core portion is held upright by engagement with the slot 64. Integral with the block 60 is an upwardly extending arcuate flange 68 provided with an arcuate slot 70 receiving'a bolt secured to an arm. as disclosed in the aforementioned Melanson patent.

The inlet pipe 56 is connected to a source of hot air 72 indicated on FIG. 1 to the passage 52 in the bracket 50 and arranged to supply the heated air to cause the adhesive on the rib 64 to become tacky and to permit subsequent attachment of the rib 24 to the insole 22 immediately thereafter. A suitable temperature for use with the specific adhesive formulations set forth below is about 275 F. i

A microswitch 74 is mounted so that its actuating arm is in contact with an abutment 78 on the lower side of the arm 12. It is necessary to provide means for shutting off the heat lamp when the machine is not being operated in order to prevent the sewing rib from overexposure or burning and consequent degradation. When an insole is to be operated on, the arm 12 is lifted by the handle 14 and an insole 22 guided over the idler roll 16 whereupon the feed fingers 20 pull the insole into the machine and simultaneously feed the rib and press it onto the insole surface. When the rib has been applied, the arm 12 is depressed, and the abutment 78 acts to open the switch74. The circuit is shown in FIG. wherein it will be seen that a main switch 80 controls the supply of current at 220 volts AC. to the lamp 30, through the switch 34. Current is also supplied to a step-down transformer 82 supply current at 115 volts A.C. to a conventional time delay unit 84 which operates to control a relay 86 connected in the supply line to the heat lamp 30. The arrangement is such that when the switch'74 is opened the time delay unit 84 acts to open the'relay 86 after" an interval pre-set by adjustment of a potentiometer 88. Thus the heat lamp 30 is cut out a predetermined time after the opening of the switch 74. If the arm 12 is lifted prior the expiration of the time delay period, the switch 74 closes and the relay 86 is not actuated. The delay period will depend upon the habits and skill of the machine operator and will average from 2 to 3 seconds, being shorter for a slower operator. The rate of feed of the ribbing is about 35 feet per minute.

THE SEWING RIB The adhesive system suitable in the present invention comprises a two layer system wherein a first layer is adhered to the rib and comprises a heat activatable composition which forms a good bond with the rib material and which'contains a dark filler such as carbon black. A second layer is applied to the first layer on the rib and comprises a heat activatable composition which forms a good bond with the insole material and which is transparent to infra-red radiation. Both layers can be formed from one or more coats and are formed of an adhesive composition which causes them to adhere to each other at normal heat activation temperatures. The first layer contains the dark filler and any filler or stabilizers such as antioxidants or other additives which may be desired. Incorporating these additives in the first layer, has the advantage of maintaining the transparency of the second layer to infra-red radiation and of promoting the flow of the second layer when heated to permit its intimate contact with the insole by filling the interstices on the insole surface. The second layer absorbs some infrared radiation and becomes heated thereby but transmits most of the radiation to the first layer for absorption by the dark filler.

It is preferred that the second layer be free of material other than the' polymeric adhesive so that it can transmit the major portion of infrared radiation to which it is exposed. However, it is to be understood that the second layer can contain a low concentration of additives opaque to infrared radiation so long as transmission of infra-red radiation through the second layer is not seriously impaired. Also, it is preferred that the second layer contain aresin such as a phenolic resin which has good tack when heated to improve adhesion of the rib and insole during the initial stage of contact.

The dark, heat absorptive filler in the first layer melting of the first adhesive layer at moderate temperatures, e.g. to C within a short time, e.g. 2 to 3 seconds. A suitable concentration for the dark filler is within the range of about 0.1 to 5.0 weight percent. Dark fillers suitable as a heat sink in the present invention include carbon black.

We begin the manufacture of the sewing rib by coating a sheet of duck or other suitable fabric 54 inches wide with an adhesive darkened with carbon black or other material. A satisfactory formulation is asfollows:

BLACK BASE LAYER 40 parts du Pont Neoprene W 25 parts Atomite (whiting, ground calcium carbonate) 10 parts Zinc Oxide 7 parts Silene EF (Calcium silicate) 2 parts Magnesium Oxide 10 parts Hydrite Flat D (soft clay) 0.8 par-ts Stearic acid a 0.8 parts Neozone A (Anti-oxidant, du Pont Naphthylamine alpha phenyl) 3 parts Carbon Black (regal 300) 30 parts Schenectady Resin SP 134 (heat reactive phenolic resin) The above ingredients are dissolved in toluene. The amount of toluene required will vary with ambient conditions. Those skilled in the art will readily understand that the amount of toluene should be sufficient to provide an adhesive compound of a viscosity suitable for use with the particular coating equipment being employed.

When the coating is dried, at second coating of the same material is applied, and when the second coating had dried, we apply a first transparent top coating designed to bond well with the fiberboard of an insole. (The system of our invention cannot satisfactorily be used upon leather insoles). A suitable formulation for the top coating is as follows:

TRANSPARENT TOP LAYER 1 5 45 parts Schenectady Resin SP553 (terpene phenolic) Toluene Solvent Here again toluene is employed as a solvent, in suitable amounts.

Another formulation suitable for use as the top coat is manufactured by A. E. Staley Manufacturing Company under N0. RM 4114. Hitherto the Staley formulation has been preferred, but we understand that the formulation is to be changed in the near future.

After the transparent top coating has dried, we apply a second coating of thesame material. The coated duck is then slit to form strips each one inch wide. Each strip is then heated to about 120 F and then passed through a machine which folds the strip over a fiberboard core strip, the margins of the fabric forming base flanges one of which is bent back upon itself as shown at 24 in FIG. 2. The folded ribbing is then wound on a spool and is ready for use.

The top coating of adhesive softens upon exposure to the heat from the lamp 30, heat which is supplemented as the ribbing passes over the passage 52 and is exposed to the hot air entering through the pipe 56. The softened top coating penetrates into the fiberboard material of the insole and crystallizes in about 24 hours to form a firm permanent bond. The base coating is adapted to make a firm bond with the fabric and also with the material of the top coating. The carbon black or other darkening material serves to render the base coating a heat sink with the result that when the base flanges of the sewing rib are pressed into contact with the fiberboard of the insole the top coating commences to crystallize or cure to form a satisfactorily strong and permanent bond.

We claim:

1. lnsole sewing rib stock comprising a core, a tape enfolding and adhered to the core and presenting base flanges extending from the core, said flanges being coated on lower surfaces thereof with an adhesive system comprising a first layer and a second layer, said first layer adhered directly on said lower surfaces and comprising a heat-activatable adhesive composition containing a dark filler and said second layer adhered to said first layer comprising a heat-activatable adhesive composition that transmits infrared radiation.

2. The rib stock of claim 1 wherein the dark filler in the first layer comprises carbon black.

3. The rib stock of claim 1 wherein the adhesive in the first and second layers comprises a mixture of polychloroprenes and said second layer contains a phenolic resin that becomes tacky when heated. 

1. INSOLE SEWING RIB STOCK COMPRISING A CORE, A TAPE ENFOLDING AND ADHERED TO THE CORE AND PRESENTING BASE FLANGES EXTENDING FROM THE CORE, SAID FLANGES BEING COATED ON LOWER SURFACES THEREOF WITH AN ADHESIVE SYSTEM COMPRISING A FIRST LAYER AND A SECOND LAYER, SAID FIRST LAYER ADHERED DIRECTLY ON SAID LOWER SURFACES AND COMPRISING A HEAT-ACTIVATABLE ADHESIVE COMPOSITION CONTAINING A DARK FILLER AND SAID SECOND LAYER ADHERED TO SAID FIRST LAYER COMPRISING A HEAT-ACTIVATABLE ADHESIVE COMPOSITION THAT TRANSMITS INFRARED RADIATION.
 2. The rib stock of claim 1 wherein the dark filler in the first layer comprises carbon black.
 3. The rib stock of claim 1 wherein the adhesive in the first and second layers comprises a mixture of polychloroprenes and said second layer contains a phenolic resin that becomes tacky when heated. 